Production of a dual-layer flow control device having improved bonding between layers

ABSTRACT

A flow control device such as a valve, damper and the like for controlling flow through a duct or other flow passage and including a relatively rigid main body portion composed primarily of a first organic resin material and a sealing portion bonded to the main body portion and composed of an elastomeric material including a second organic resin. The bond between the sealing portion and main body portion is increased by mixing some of the second organic resin material with the first organic resin material. Mounting means in the form of a pivot rod is molded to the main body portion for pivotally supporting the device in a duct or the like. The device can be made by a method including steps of mixing the second organic resin in powdered form into a quantity of the first organic resin in liquid form and then pouring the mixture into a portion of a mold defining the configuration of the main body portion. Elastomeric material for the sealing portion is poured into the mold in liquid form and covers the surface of the mixture of the first organic resin and the powdered form of the second organic resin. The contents of the mold is then cured.

This is a divisional of application Ser. No. 259,721, filed June 5,1972, now U.S. Pat. No. 3,804,366.

This invention relates generally to flow control devices such as valves,dampers and the like for controlling flow through a duct or other flowpassage, and is particularly concerned with a flow control deviceconstructed of organic resin material and suitable for use in airconditioning, heating and ventilation systems of automobiles, and to amethod and apparatus for manufacturing such flow control devices.

Flow control devices in the form of dampers of Butterfly-type valves areparticularly suitable for controlling the flow through automobileventilation, air conditioning and heating ducts due to the ease andspeed with which such devices can be manipulated. One of the problems ofsuch devices is that of obtaining a good seal when the flow controldevice is in a closed position to shut off flow through the ductcontrolled thereby. This problem is of course magnified when the ductsand flow control devices must be produced on a mass production basis sothat economic tolerances can be maintained for both the ducts and theflow control devices commensurate with the requirements forinterchangeability of the products. For large quantity production, it isof course also necessary to maintain production and material costs to aminimum.

A flow control device of this type must have a relatively rigid mainbody portion to which mounting means such as a pivot rod or the like canbe secured, and must have a peripheral sealing portion for engagementwith the inner walls of the duct being controlled by the flow controldevice.

The prior U.S. Pat. No. 3,753,549 of Phillip L. Rubright, assigned tothe assignee of this application, discloses a flow control device havinga main body portion of rigid plastic material and a sealing portion ofelastomeric material on the periphery thereof. The latter U.S. Pat. No.3,753,549 also discloses a method of making a flow control device byconfining elastomeric material in liquid state in a portion of a molddefining the configuration of the sealing portion of the device,partially curing the elastomeric material to change it to a non-liquidstate, and then confining thermosetting resin in liquid state in asecond portion of the mold defining the configuration of the main bodyportion such that the liquid resin flows into contact with the partiallycured elastomeric material and simultaneously curing the resin andcompleting curing of the elastomeric material. The liquid elastomericmaterial is poured into a portion of the mold and flows into contactwith a heated, removeable mold member defining the inner periphery ofthe elastomeric sealing portion. When the liquid elastomeric materialflows into contact with the heated removeable mold member, it gelsimmediately to prevent the elastomeric material from leaking around theremoveable mold member. The removeable mold member is then removed fromthe mold and liquid thermosetting resin is poured into the mold and issurrounded by the partially cured elastomer.

The present invention has for one of its primary objects thesimplification of the manufacturing of this type of device byeliminating the necessity of partially curing the elastomer prior tocuring the thermosetting resin so that both the elastomeric material forthe sealing portion of the device and the thermosetting resin of themain body portion of the device can be simultaneously cured from aliquid state.

A further object of this invention is to provide a composite dual layerflow control device such as a vane for a butterfly valve or the like,the vane having a relatively rigid main body portion of organic resinmaterial and an elastomeric sealing portion including organic resinmaterial wherein the bond between the sealing portion and main bodyportion is increased.

In accordance with the present invention, the flow control deviceincludes a relatively rigid main body portion or layer composed of afirst organic resin material and a sealing portion or layer overlyingthe main body portion, and projecting from the periphery thereof, thesealing portion being composed of elastomeric material including asecond organic resin. The bond between the main body portion and thesealing portion is increased by mixing a powdered form of the secondorganic resin with the first organic resin. The first organic resin maybe a thermosetting epoxy resin and the main body portion formed therebymay include a plurality of openings or the like so that the main bodyportion comprises a grid-work or frame for supporting the continuouselastomeric sealing portion. That is to say, the elastomeric sealingportion will overlie one side of the frame or grid-work making up thebody portion and will extend across the openings in the frame orgrid-work. A pivot rod is embedded in the body portion for pivotallymounting the device in a duct or the like.

In the manufacture of the flow control device, the first organic resinin liquid form, such as thermosetting epoxy resin, has mixed therewith aselected quantity of a second organic resin, such as polyvinyl chloride,in powdered form. The mixture is confined in a portion of a molddefining the configuration of the body portion of the flow controldevice, and a pivot rod is placed on the mold such that a portion of thepivot rod is immersed in the liquid mixture. A plastisol containing thesecond organic resin, for example, a vinyl plastisol, is then poured inliquid form into the mold and covers the surface of the mixture of thefirst organic and the powdered form of the second organic resin. Themold and the entire contents are then placed in a curing oven or thelike to cure the contents of the mold and solidify the plastisol and thefirst organic resin.

Other objects, advantages and features of the invention will becomeapparent from the following description given in connection with theaccompanying drawings in which:

FIG. 1 is a cross-sectional view of a duct having flow control deviceaccording to the invention mounted therein;

FIG. 2 is a sectional view taken on line 2--2 of FIG. 1;

FIG. 3 is a plan view of molding apparatus for making the flow controldevice shown in FIGS. 1 and 2;

FIGS. 4 through 7 are sectional views of the molding apparatus of FIG. 3sequentially illustrating a method of manufacturing the flow controldevice of FIGS. 1 and 2;

FIG. 8 is a view similar to FIGS. 4 through 7 illustrating analternative step in the method of manufacturing the flow control device;

FIG. 9 is a sectional view of an alternative construction of a mold; and

FIG. 10 is a cross-sectional view of a duct having a flow control devicemounted therein and constructed according to a second form of theinvention.

In FIGS. 1 and 2, reference numeral 2 collectively designates a flowcontrol device according to the invention, such as a vane or a butterflyvalve or the like, the vane having a relatively rigid body portion 4composed primarily of organic resin material such as thermosetting epoxyresin, and an elastomeric sealing portion 6 bonded to the body portion 4and projecting outwardly from the periphery thereof to define a sealingedge for the flow control device 2. As shown in FIGS. 1 and 2, thesealing portion 6 comprises one layer of the dual-layer flow controldevice that extends across one entire surface of the body portion 4 andalso projects beyond the edges thereof. Mounting means 8 for ppivotablymounting the flow control device 2 in a duct 10 comprises a rod moldedto or imbedded in the body portion 4.

The rod 8 has a central portion 12 embedded in the material of the bodyportion 4, and offset end portions 14 and 16 on the central portion bothof which project from one side of the body portion 4 and throughopenings in the wall of the duct 10 for pivotally mounting the flowcontrol 2 in the duct. The central portion 12 has outwardly bentportions 18 and 20 projecting from the main body portion 4, the endportions 14 and 16 extending respectively from the bent portions 18 and20. A crank arm 22 is formed on the end portion 14 for connection with acable or similar operating means.

The body portion 4 of the control device 2 comprises a flat disc with aperipheral flange 24 projecting from one side thereof in the directionof the axis of duct 10. A central bead 26 projects from the same side 23of the disc forming the body portion 4, and the central portion 12 ofthe mounting rod 8 extends in parallel relationship with bead 26. A bead28 extending transversely of the bead 26 is also formed on the bodyportion 4 and projects from side 23 thereof. A locating projection 30 isformed on the periphery of the disc or body 4 for providing verticalsupport of the body portion 4 in the duct 10.

In the embodiment illustrated in FIGS. 1 and 2, flow control device 2 isof non-circular configuration in plan, and the width of the sealingportion 6 that projects from the periphery of the body portion 4 variesin width around the circumference of the body portion 4. The top segment34 and sides 36 and 38 of the elastomeric sealing portion 6 are ofsubstantially the same width, while the bottom segment 40 is ofsubstantially the same width, while the bottom segment 40 is ofsubstantially less width than segments 34, 36 and 38. The segment 42 ofthe portion of elastomeric sealing portion that projects beyond thelocating projection 30 is of substantially less width than the segments34, 36 and 38. Vertical or axial support of the control device 2 isprovided by the locating projection 30, so that the entire periphery ofsealing portion 6 is in good sealing engagement with the inner walls ofthe duct 10.

The openings in the duct 10 for the end portions 14 and 16 of themounting rod 8 are on the downstream side of the control device 2 sothat there is no likelihood of leakage through such openings on theupstream or high pressure side of the control device 2. The highpressure side is the right hand side of the control device 2 in FIG. 2of the drawings. The end portions 14 and 16 will generally be located onthe passenger compartment side of the control device 2 where it is notcritical to prevent the leakage from the duct 10.

The thin portion 42 of the sealing portion 6 provides a seal beneath thelocating projection 30 without a significant amount of deflection of theelastomeric portion 32, so that the upper segment 34 of the sealingportion 6 is in good sealing contact with the upper wall of the duct 10.The mounting rod 8 provides transverse support for the control devicesuch that the side segments 36 and 38 of the sealing portion 6 are inclose sealing contact with the respective side wall of the duct.Consequently, when the control device 2 is in the fully closed positionillustrated in FIGS. 1 and 2, there will be no flow through the ductpast the control device 2.

The body portion 4 of the control device 2 is composed primarily of arelatively rigid organic resin such as thermosetting epoxy resin. Theelastomeric sealing portion 6 bonded to the body portion 4 is composedof a plastisol containing an organic resin different from the organicresin of the body portion 4. By plastisol is meant a liquid dispersionof finely divided resin in a plasticizer. It is usually 100% solid withno volatiles, and when the volatile content exceeds 5% of the totalweight, it is referred to as an organosol. When the plastisol is heated,the plasticizer solvates the resin particles, and the mass gels. Withcontinued application of heat the mass fuses to become a conventionalthermoplastic material. In order to increase the bond between the bodyportion 4 and the sealing portion 6, the same organic resin, in powderedform that is contained in the plastisol, is mixed into the liquidorganic resin that forms the body portion 4.

The control device 2 may be made by mixing polyvinyl chloride powderinto liquid epoxy. It has been found that the most satisfactory resultsare obtained when 10 to 20% of polyvinyl chloride powder by weight ismixed with liquid epoxy resin. The mixture of the liquid epoxy resin andpolyvinyl chloride powder is then confined in a portion of a molddefining the configuration of the body 4. The mounting rod 8 is thenplaced on the mold so that portion 12 is immersed in the liquid mixtureof the polyvinyl chloride powder and epoxy resin. A vinyl plastisol inliquid form is then poured or "floated" over the surface of the epoxyresin to the desired thickness of the sealing portion 6. The entirecontents of the mold are then cured by placing the mold into a curingoven to solidify the plastisol and epoxy resin.

FIGS. 3 through 9 illustrate a molding apparatus and the various stepsin the manufacturing of the control device 2. In FIG. 3, referencenumeral 50 collectively designates a mold body having legs 52, 54 and56. A cavity is formed in the mold 50 including a first mold portion 58having a bottom surface 60 for defining one side surface of the portionof the sealing portion 6 that projects beyond the body 4, the outerperiphery of the sealing portion 6 being defined by an edge surface 62of the mold. The mold cavity includes a second mold portion 64 having abottom surface 66 for defining one side surface of the body portion 4 ofthe control device 2. Transverse recesses 72 and 74 are formed in thebottom 66 of the second mold portion 64 for defining the beads 28 and26, respectively, on the body portion 4. The mold portion 64 is alsoformed with a peripheral recess 76 for defining the peripheral flange 24of the body 4.

The bottom surface of the first and second mold portions 58 and 64 arenon-circular in plan, and the width of the bottom surface of the firstmold portion 58 varies around the periphery of the second mold portion64 in accordance with the configuration of the segments 34, 36, 38, 40and 42 of the sealing portion 6 of the control device 2. The bottomsurface 66 of the mold portion 64 projects outwardly as illustrated at78 toward the edge surface of the mold portion 58 to define the locatingprojection of the body of 4.

Rod supporting means are formed on the mold apparatus of FIGS. 3, 4 and5, and include a pair of grooves 80 and 82 spaced from each other onopposite sides of the first and second mold portions, grooves 80 and 82being formed in the rim 84 extending around the periphery of the moldbody 50. The rod supporting means further includes a projection 86extending outwardly from the rim 84 and having a rod receiving recess 88formed therein which is in axial alignment with the grooves 80 and 82.The projection 86 includes a pair of crank arm locating slots 90 and 92each communicating with the recess 82 for supporting the crank arm 22 ofthe mounting rod 8. The slot 90 is used to support a crank arm of oneconfiguration, and slot 92 is used to support a crank arm of a secondconfiguration, as necessary. Slots 90 and 92 angularly locate themounting rod with the mold cavity portions 58 and 64.

With reference to FIG. 4, the first step in the method of making thecontrol device 2 comprises confining a mixture of liquid organic resinfor the body 4 with organic resin used in the plastisol for the sealingportion 6 in powdered form in the mold as indicated in FIG. 4. Themixture is poured into the mold to the level indicated at 4a by thedotted lines, or to the level defining the surface of the body 4 towhich the sealing portion 6 is to be bonded. The second step isillustrated in FIG. 5, and the mounting rod 8 is placed on the mold suchthat the central portion 12 of the mounting rod 8 is immersed in themixture of the liquid and powdered organic resins. The third step isillustrated in FIG. 6, wherein the liquid plastisol containing adispersion of the same organic resin that is mixed in powdered form withthe liquid organic resin forming the body portion 4 is poured or"floated" onto the upper surface of the mixture to the depth indicatedat 6a and defined by the edge portion 62 of the mold. The mold and theentire contents are then placed into a curing oven to solidify the layerforming the body portion 4 and the layer forming the sealing portion 6,as illustrated in FIG. 7.

An alternative step in the method described in the preceding paragraphis illustrated in FIG. 8, wherein liquid epoxy resin is poured into themold before it is mixed with the powdered resin of the plastisol. Themounting rod 8 is then placed onto the mold with the central portion 12thereof immersed in the liquid epoxy resin. Powdered polyvinyl chloride,indicated by reference numeral 7 is then sprinkled over the surface ofthe liquid epoxy resin to form a mixture of liquid epoxy resin andpowdered polyvinyl chloride. Vinyl plastisol is then poured or "floated"onto the surface of the epoxy, as in the previously defined step inconnection with FIG. 6. The mold is then placed into a curing oven tocure the materials contained in the mold.

A modified form of the control device is illustrated in FIG. 10, whereinthe control device 2 includes body portion 4' in the form of arelatively rigid framework, having a plurality of openings 100 extendingtherethrough. The sealing portion 6' of the control device 2' extendsacross one surface of the body 4' and closes the openings 100. Theconfiguration of the body 4' can be formed in a mold as illustrated inFIG. 9, which is identical to the previously described molds, except forthe addition of projections 98 extending upwardly from the bottomsurface 66 of the mold to form the openings 100 through the body portion4'. Obviously, other configurations of the body 4 can be provided byaltering the mold accordingly.

While specific forms of the invention have been illustrated anddescribed in the accompanying drawings and the foregoing specification,it will be apparent to those skilled in the art that the invention isnot limited to the exact construction shown, or to the exact stepsdescribed, but that variations in the construction and method, allfalling within the scope and spirit of the invention, will be apparentto those skilled in the art.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A method of making acomposite, dual-layer flow control device having a relatively rigid bodyportion of organic resin material and an elastomeric sealing portionbonded to said body portion, said method comprising the steps of:confining a mixture of a first organic resin in liquid form and a secondorganic resin in powdered form in a portion of an openface mold definingthe configuration of said body portion with said mixture reaching afirst level in said mold, pouring a liquid plastisol containing saidsecond organic resin into said mold until said plastisol covers thesurface of said mixture and reaches a second level in said mold, andcuring the contents of said mold to solidify the plastisol and saidmixture and integrally bond the materials together.
 2. A method asclaimed in claim 1 wherein said second organic resin in powdered form ismixed with said first organic resin in liquid form by first pouring saidfirst organic resin into said mold and then sprinkling a selectedquantity of said second organic resin onto the surface of said firstorganic resin.
 3. A method as claimed in claim 1 including the step ofimmersing a pivot rod in said mixture prior to introduction of saidliquid plastisol into said mold so that the pivot rod will be embeddedin the body portion upon curing.
 4. A method as claimed in claim 1wherein said first organic resin is thermosetting epoxy resin.
 5. Amethod as claimed in claim 4 wherein the plastisol is vinyl plastisol.6. A method as claimed in claim 1 wherein the plastisol is vinylplastisol.
 7. A method of making a composite device having a first rigidbody portion composed of material that is liquid in its uncured stateand includes a first organic resin, and a second elastomeric portioncomposed of material that is liquid in its uncured state and has atleast two ingredients, one of said ingredients being a second organicresin, said method comprising the steps of: mixing a selected quantityof one of the ingredients of said second portion with the material ofsaid first portion in the uncured liquid state of the material of saidfirst portion; pouring the mixture into an open face mold; pouring thematerial of the second portion in its uncured liquid state into the moldand covering at least a portion of the surface of said first portionwith the material of said second portion in its uncured state; andcuring said materials.
 8. A method of making a composite, dual layervane for a butterfly valve or the like wherein the vane has a relativelyrigid body portion consisting primarily of a first organic resinmaterial and an elastomeric sealing portion consisting primarily of asecond organic resin material bonded to said body portion and projectingoutwardly from the periphery thereof, said method comprising the stepsof: pouring a quantity of said first organic resin material in liquidform into an open-face mold to a first level such that said firstorganic resin material is confined in a portion of the mold defining theconfiguration of said body portion; supporting a pivot rod on the moldsuch that at least a portion of said pivot rod is immersed in said firstorganic resin; sprinkling a selected quantity of said second organicresin in powdered form onto the surface of said first organic resin;pouring a liquid plastisol containing said second organic resin intosaid mold and covering the surface of said first organic resintherewith; and then curing the contents of said mold to solidify saidresins and bond said first and second resins together with said pivotrod imbedded in at least the body portion of said vane defined by saidfirst organic resin.
 9. A method of making a composite, dual layer vanefor a butterfly valve or the like wherein the vane has a relativelyrigid main body portion consisting primarily of a first organic resinmaterial and an elastomeric portion consisting primarily of a secondorganic resin material bonded to said body portion and projectingoutwardly from the periphery thereof, said method comprising the stepsof: pouring a mixture of said first organic resin in liquid form andsaid second organic resin in powdered form into an open-face mold to afirst level such that said mixture is confined in a portion of the molddefining the configuration of said body portion; supporting a pivot rodon said mold such that at least a portion of said rod is immersed insaid mixture; pouring a liquid plastisol containing said second organicresin into said mold until said plastisol covers the surface of saidmixture and reaches a second level in said mold; and then curing thecontents of said mold to solidify said resins and bond said first andsecond resins together with said pivot rod imbedded in at least the bodyportion of said vane defined by said first organic resin.